The present invention relates to a method of manufacturing a semiconductor device. For example, the invention is effectively used for a manufacturing technique of a semiconductor device including a nonvolatile memory cell.
An electrically erasable and programmable read only memory (EEPROM) and a flash memory are each widely used as an electrically writable and erasable nonvolatile memory cell. Such a nonvolatile memory cell includes a floating gate electrode surrounded by an insulating film such as an oxide film or a trapping insulating film below a gate electrode of a metal insulator semiconductor field effect transistor (MISFET), and uses a charge state stored in the floating gate electrode or the trapping insulating film as storage information. The trapping insulating film refers to a charge-storable insulating film, and exemplarily includes a silicon nitride film. A metal-oxide-nitride-oxide-semiconductor (MONOS) transistor (memory transistor) is widely used as such a nonvolatile memory cell.
For example, International Publication No. WO 2015/112245 describes a manufacturing technique of a semiconductor device including a nonvolatile memory and a field effect transistor.